Machine for conveying bulk material and control therefor



Jan. 24, 1956 M. c. ADDICKS MACHINE FOR CONVEYING BULK MATERIAL ANDCONTROL THEREFOR 7 Sheets-Sheet 1 Original Filed May 12, 1952 INVENTOR.MM) 444% Jan. 24, 1956 M. c. ADDICKS MACHINE FOR CONVEYING BULK MATERIALAND CONTROL THEREFOR 7 SheetsF-Shaet 2 Original Filed May 12, 1952 MnmnmINVENTOR. mp 63AM Jan. 24, 1956 M. c. ADDICKS Re. 24,112

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MACHINE FOR CONVEYING BULK MATERIAL AND CONTROL THEREFOR Original FiledMay 12, 1952 7 Sheets-Sheet 4 I N VEN TOR.

Jan. 24, 1956 M. c. ADDICKS Re. 24,112

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Jan. 24, 1956 M. c. ADDICKS Re. 24,112

MACHINE FOR CONVEYING BULK MATERIAL AND CONTROL THEREFOR Original FiledMay 12, 1952 7 Sheets-Sheet 7 FULL AER IN VEN TOR.

United States Patent MACHINE FOR CONVEYING BULK MATERIAL AND CONTROLTHEREFOR Mentor C. Addicks, Minneapolis, Minn.

Original No. 2,699,919, dated January 18, 1955, Serial No. 287,396, May12, 1952. Application for reissue August 29, 1955, Serial No. 531,310

18 Claims. (Cl. 254187) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

My invention relates generally to machines for handling granular or bulkmaterial and, more specifically, to improved mechanism for conveyingbulk material from a given location to a point of delivery remotetherefrom.

More particularly, my present invention is in the nature of amodification of the structure disclosed and claimed in my co-pendingapplication Serial No. 209,175, filed February 2, 1951, now Patent No.2,646,965 issued July 28, 1953, and entitled Device for HandlingGranular Material."

An important object of my invention is the provision of'a cable windingdrum for pulling a material-handling drag or scoop in one direction andof novel means for preventing backlash or overrunning of the drum whenthe cable is being unwound therefrom.

Another object of my invention is the provision of a cable winding drumand a drive shaft therefor having a releasable high torque transfercoupling and a low torque transfer coupling connecting the drive shaftto the drum, and of novel means for varying the torque transferabilityof the low torque transfer coupling.

Another object of my invention is the provision of conveying mechanismas set forth which is relatively simple and inexpensive to build andinstall, which is efficient in operation and which is rugged inconstruction and durable in use. I

Still another object of my invention is the provision of a novelarrangement whereby a plurality of winding drums of the above type maybe utilized in cooperation to move a material-handling scoop or dragover a relatively wide area and in various directions of travel withoutchanging the locations of the winding drums.

A still further object of my invention is the provision of novel controlmeans for conveying machines of the type set forth.

Another object of my invention is the provision of control means forconveying machines of the above type which may be easily carried by theoperator, so as to enable the operator to be stationed at the mostadvantageous point for observation and control of the conveyingoperations.

The above and still further highly important objects and advantages ofmy invention will become apparent from the following detailedspecification, appended claims and the accompanying drawings.

Referring to the drawings, which illustrate the invention, and in whichlike characters indicate like parts throughout the several views:

Fig. 1 is a diagrammatic view in horizontal section of a mine shaft orthe like showing one of the operative arrangements of my novel conveyingequipment;

Fig. 2 is an enlarged view in plan of one of the conveying machines ofmy invention, some parts being broken away;

Fig. 3 is a view in side elevation of the machine of Fig. 2, some partsbeing broken away and some parts shown in section;

Fig. 4 is an enlarged transverse section taken on the line 44 of Fig. 3,some parts being broken away;

Fig. 5 is an enlarged transverse section taken substantially on the line5-5 of Fig. 2, some parts being broken away;

Fig. 6 is a fragmentary detail as seen from the line 6-6 of Fig. 5;

Fig. 7 is a fragmentary detail as seen from the line 7-7 of Fig. 5;

Fig. 8 is a greatly enlarged fragmentary detail of a portion of Fig. 3;

Fig. 9 is a view in plan of a single drum machine of Fig. 1, some partsbeing broken away;

Fig. 10 is a view in side elevation of the structure of Fig. 9, someparts being broken away;

Fig. 11 is a diagram showing the control circuits utilized in thearrangement illustrated in Fig. 1;

Fig. 12 is a view in plan of the control switch of the invention ofFigs. 1 to 11, inclusive;

Fig. 13 is a view in side elevation of the control of Fig. 12, someparts being broken away;

Fig. 14 is a view in end elevation of said control;

Fig. 15 is a diagrammatic illustration of a modified arrangement of mynovel material-handling equipment;

Fig. 16 is a wiring diagram illustrating the electrical circuitsutilized in the equipment of Fig. 15; and

Fig. 17 is a view corresponding to Fig. 5, but showing a modified formof the invention.

In the conveying of granular or bulk material from one location toanother, where the material must be delivered around obstructions suchas corners and through branch corridors as are found in mines and thelike, and when utilizing a drag or scoop, I have found it advisable touse a plurality, preferably three, of cable winding drums, as indicatedat A, B and C. A length of cable D has one end portion Wound on the drumA and is connected at its other end to the front portion of a dragshovel or scoop E. The cable D is utilized to pull the scoop E from thesource of material designated at F at one end of a mine corridor or thelike G, through a branch corridor H to a loading hopper or the like I. Apull-back cable K has one end portion wound on the drum B and isconnected at its other end to the rear portion of the scoop B, saidcable K running in and being guided by suitably placed tail sheaves andthe like L and M secured by suitable means, not shown, to the walls ofthe mine or other structure. Where necessary, a guide roll N is utilizedto prevent the pull-back cable K from rubbing against the corner betweenthe two corridors G and H. A third length of cable 0 has one end portionwound on the drum C and has its other end slidably connected to a bar Pextending from the front to the rear of the scoop E. As will hereinafterbe explained, the cable 0 will, during one portion of the operation, beutilized as a pull-forward cable, whereas at another stage of theoperation, the cable 0 will be utilized to move the scoop E in abackward or return direction.

The pull-forward drum A and the pull-back drum B are independentlyjournaled on a drive shaft 1 which is journaled in suitable bearings 2that are rigidly mounted on a generally rectangular supporting frame 3.Continuous and uninterrupted rotary movement is imparted to the driveshaft 1 by a motor 4, on the shaft 5 of which is mounted a drive pinion6. The pinion 6 has meshing engagement with a gear 7 which is keyed orotherwise rigidly secured to one end of the drive shaft 1, see Figs. 1to 3, inclusive.

The cable winding drum C, see Figs. 1, 9 and 10, is journaled on a driveshaft 8 which is, in turn, journaled in bearings 9 rigidly mounted on asupporting frame structure 10. The continuous and uninterrupted rotationis imparted to the drive shaft by a motor 11 to the shaft 12 of which isrigidly secured a pinion 13 which has meshing engagement with a gear 14rigidly secured to one end of the drive shaft 8 for common rotationtherewith.

The drums A, B and C are identical and are each driven by theircooperating drive shafts by means of separate releasable high torquetransfer couplings, and each by a separate low torque transfer coupling.The high torque transfer couplings are identical as are the low torquetransfer couplings associated with each drum; hence for the sake ofbrevity but one of each will be described in detail, the referencecharacters identifying the several parts of one of each thereof alsobeing utilized to identify corresponding parts of the others thereof.The high torque transfer coupling of the drum A is designated in itsentirety at 15, that of the winding drum B being designated in itsentirety at 16, and that associated with the winding drum C beingindicated in itsentirety at 17. The high torque transfer coupling 15comprises driving and driven clutch elements 18 and 19, respectively.The driving element 18 is in the nature of a fluid pressure operatedexpansible and retractable clutch member having a plurality of frictionshoes or the like 20 secured thereto for gripping engagement with thedrum 19. The member 18 is made in the form of an annular tube fromrubberlike material and defines an expansion chamber 21. The outerperipheral portion of the member 18 is suitably anchored to an annularflange 22 which, in turn, is rigidly secured to and carried by amounting plate 23 having a hub 24 which is keyed or otherwise anchoredto the drive shaft 1, as indicated at 25, see Fig. 3. The releasablehigh torque transfer couplings 15 to 17, inclusive, are of the typedisclosed in the United States Letters Patent to Thomas Fawick, No.2,237,864.

Fluid such as air under pressure is admitted to the chambers 21 of thecouplings 15 and 16, from a suitable source, not shown, through aconduit 26 in which is interposed a conventional pressure regulatorvalve 27, and branch conduits 28 and 29, respectively, in which areinterposed solenoid operated valves 30 and 31, respectively. Theconduits'28 and 29 terminate in elbow-like fittings 32 at opposite endsof the shaft 1 and which communicate with axially extended passages 33therein, see Fig. 3. The passages 33 communicate with axial passages,not shown, but which may be assumed to extend through the hubs 24, toeach of which is connected an extension conduit 34 which communicateswith the chamber 21 of its respective clutch or driving element 18. Thesolenoids for operating the valves 30 and 31 are conventional in natureand may be assumed to be contained in casings 35. Energization of thesolenoidscontained in the casings 35 permits air under predeterminedpressure to enter the chambers 21, whereby to cause engagement of theclutch members 18 with the respective clutch or driven elements 19. Whensaid solenoids are de-energized, their respective valves 30 and 31 arepositioned as to cause communication of the respective chambers 21 withatmosphere. The structure of the clutch elements 18 is such that thefriction shoes 20 thereof are normally out of engagement with' the drum19, so that when the chambers 21 are open to atmosphere, the drivingconnection between the driving and driven elements 18 and 19,respectively, is released.

With reference to Figs. 9 to 11, inclusive, it will be seen that thehigh torque transfer coupling 16 is supplied with air under pressurefrom the source of supply through a conduit in which is interposed asolenoid operated valve 37 identical to the valves 30 and 31.

As above indicated, the drums A, B and C are each provided with a lowtorque transfer coupling 38, 39 and 40, respectively. The low torquetransfer couplings are identical and each comprises driving and drivenelements 41 and 42, respectively, the latter being in the nature of acylindrical friction surface formed on a hub 43 of its respectivewinding drum. The driving element 41 comprises a circumferentiallyextending friction shoe or band 44 having opposed outturned flanges 45and 46 at its opposite ends. A wing nut-equipped adjustment screw 47extends through aligned apertures in the flanges 45 and 46 and a coiledcompression spring 48 encompasses the bolt 47 between the flange 45 andsaid wing nut which is indicated at 49. The spring 48 exerts a yieldingbias against the flange 45 and the wing nut 47 in a direction to causethe band 44 to frictionally engage the surface of its cooperating hub43. This frictional engagementor pressure may be varied by tightening orloosening of the wing nut 49 on the bolt 47. The band 44 is providedwith a radially outwardly projecting lug 50 which is confined betweenlaterally projected legs 51 of a plate 52 that is bolted or otherwiserigidly secured to an arm 53 integrally formed with and projectingradially outwardly from a hub 54 that is rigidly secured to the driveshaft 1 by means of a key 55 and a set screw 56. As shown in Figs. 4 to6, inclusive, a cotter pin or the like 57 extending through alignedapertures in the outer ends of the legs 51 confines the lug 50 betweenthe legs 51 in a direction axially of the drive shaft 1. Integrallyformed with the hub 54 and projecting radially outwardly therefrom indiametrically opposed relationship to the arm 53 is a second arm 58. Aguide plate 59 is rigidly secured to the outer end of the arm 58 andextends outwardly therefrom in a direction axially of the drive shaft 1,the outer end thereof overlying a portion of the band 44. The outer endportion of the plate 59 is provided with a recess or notch 60 in whichis received a lug 61 which projects radially outwardly from the band 44.The plate 59 confines the band 44 against axial movement on the hub .43and prevents relative rotary movement between the shaft 1 and the band44 in one direction.

When rotation is impartted to the shaft 1 by the motor 4, the high andlow torque transfer coupling driving elements 15 and 41, respectively,being rigid therewith, rotate in the same direction. The air chambers 21of the high torque transfer couplings 15 and 16 being in communicationwith atmosphere to the valves 30 and 31, respectively, there is nodriving engagement between the driving elements 15 and driven elements19 of the high torque transfer couplings. However, when the high torquetransfer couplings 15 and 16 are thus released, the drums A and B tendto rotate in the same direction as that of the drive shaft 1 due to thefrictional loading between the driving and driven elements 41 and 42,respectively, of the low torque elements 38 and 39. With reference toFig. 1 it will be seen that the length of cable D is partially wound onthe drum A in one direction while a portion of the pull-back or returncable K is wound upon the drum B in the opposite direction. Hence, whenthe high torque transfer coupling 15 of the drum A is set, a high torquedriving load'is placed upon the drum A, causing the pull-forward cable Dto be wound thereon. Obviously, at this time, there is no differentialin speed between the driving and driven elements of the low torquetransfer coupling 38 associated with the drum A. The pull-back cable Kbeing connected to the rear of the scoop E to which the pull-forwardcable D is also connected, winding up of the cable D upon the drum Awill cause the pull-back or return cable K to be unwoundfrom the drum B,thereby causing the drum B to be rotated in a direction opposite to thedirection of rotation of the drive shaft 1. Thus, the driving and drivenelements 41 and 42 of the low torque transfer coupling 29 are rotatingin opposed directions. When the high torque transfer coupling 15 isreleased, rotation of the drum A will cease almost instantaneously dueto the load placed thereon by the drag or scoop E. The frictional loadof the low torque coupling 39 is sufiicient to overcome the inertia ofthe winding drum B which, as above stated, has been rotating in theopposite direction, so as to effectively prevent overrunning of the drumB and consequent undue slack in the return cable K, which mightotherwise result in backlash. It is highly important that the tension orforce of the low torque transmission be made adjustable. The location ofmachine installations with relation to the material being conveyed willnecessitate" considerable variations in the lengths of cable used, andtherefore the required torque to keep the return or pull-back cableunder tension will vary. Also changes of temperature between winter andsummer aflects the expansion and contraction of cable, and wear ofclutch parts and various bearings may also necessitate change inadjustment of the tension of the low torque transmission. Bymanipulation of the adjusting nut 49 on the low torque transfercoupling, the low torque transferability of said couplings may beadiusted to maintain the slack in the unwinding cable at a minimumwithout imposing an undue load on the drum A and the cable D being woundthereon. When the scoop E is being returned to its point of loading, bysetting the high torque transfer coupling 16 and causing the returncable K to be wound on the drum B, the low torque transfer coupling 38associated with the drum A will operate to prevent overrunning in thedrum A and backlash in the cable unwinding therefrom upon realease ofthe high torque transfer coupling 16 associated with the drum B andcessation of rotation of the drum B.

For controlling the operation of the drums A and B as well as the drum Cin an arrangement such as illustrated in Fig. 1, a pair of controlswitches 62 and 63 are utilizedin an electrical circuit including thesolenoid associated with the valves 30, 31 and 37. As shown, a pair ofleads 64 and 65 are connected to opposite sides of a power line 66. Amain switch 67 is interposed in the leads 64 and 65, the leads 64 beingconnected to the solenoids of the valves 30, 31 and 37 by branch leads68, 69 and 70, respectively. The switch 62 comprises a pivotally mountedelement 71 which is movable between spaced switch contacts 72 and 73,the former of which is connected to the solenoid of the valve 30 byalead 74 and the latter of which is connected to the solenoid of thevalve 31 by a lead 75. The switch 63 comprises a pivotally mountedswitch element 76 movable between spaced contact elements 77 and 78 thatare connected by a common lead 79 to the solenoid associated with the.valve 37 of the winding drum C. As shown, the switchselements 71 and 76both may be maintained in an off position between their respectivecontacts. As diagrammatically shown in Fig. 11, the switch elements 71and 76 are connectedfor common movements by means including a bar 80which will hereinafter be more fully described.

Preferably and as shown in Figs. 1 and 151, the wires from the solenoidsof the switches 30, 31 and 37 and leading to the switches 62 and 63 areconfined in long cables 81 and 82, the latter of which terminates in aportable controller 83 which may be easily carried about by theoperator, indicated at R. The controller 83 includes a pair of switchhousings 84 and 85 which contain the switches 62 and 63, respectively,see Figs. 12-14, inclusive.' As shown, the movable switch element 71 isconnected to a shaft 86 journalled in the housing 84 and to the outerend of which is rigidly secured the lower end of a crank arm 87.Similarly, the movable element 76 of the switch 63 is secured at itslower end to a shaft 88 which is journaled in the housing 85 and hassecured to its outer end the lower end of a crank arm 89. The actuatorbar 80 is made up of a pair of telescoping sections 90 and 91, theformer of which is connected at its outer end to the upper end of thecrank arm 87 by a ball and socket connection 92, and the latter of whichhas its outer end connected to the upper end of the crank arm 89 by asimilar ball and socket connection 93. As shown particularly in Fig. 13,the bar section 90 is longitudinally movable with respect to itscooperating section 91 and is provided with a transverse pin 94 whichmoves within a longitudinally elongated slot 95 in the section 91. The

extent of the slot 95 limits the amount of relative longitudinalmovement between the bar sections 90 and 91, for a purpose which willhereinafter become apparent. As above noted, the operator R, incontrolling the operation of the several drums A, B and C in anarrangement as illustrated in Fig. 1, may station himself at anyconvenient or advantageous location. When the scoop E is in its fullline position of Fig. 1 and moving toward the discharge hopper J, thecable D is being wound upon the drum A while the cables K and 0 arebeing unwound from their respective drums B and C. Otherwise stated, thehigh torque transfer coupling 15 is set whereas the high torquecouplings 16 and 17 are released. Also, during this time, the switch arm76 of the switch, is at its off position, whereas the switch arm 71 ofthe switch 62 is positioned to close the circuit to the solenoidoperated valve 30 through the contact 72, the leads 64, 65 and 74 andthe branch leads 68. During the forward travel of the scoop E, thecables K and O are under tension caused by the drag imposed upon theirrespective drums B and C by the low torque transfer couplings associatedtherewith. As soon as the scoop E reaches thehopper I and dischargesmaterial thereinto, the operator manipulates the actuator bar to connectthe switch arm 76 with one of the contacts 77 or 78 and to move theswitch arm 71 to its off position. coupling 17 of the drum C is therebyset and the scoop E is pulled backwardly through the corridor H by thecable 0, the resultant slack in the cable K being immediately taken upby winding rotation of the drum B, said winding rotation being impartedthereto by the low torque transfer coupling 39 associated therewith.Simultaneously, the cable D is being unwound from the drum A. When thescoop E has been pulled by the cable 0 into the gallery G, the operatormanipulates the actuator bar 80 to place the switch 63 in its 05position and closes the connection between the switch arm 71 of theswitch 62 and the contact 73 thereof, whereby to release the high torquetransfer coupling 17 of the drum C and to set the high torque transfercoupling 16 of the drum 'B. The pullback or return cable K is then woundupon the drum B, thus pulling the scoop E backwardly toward the tailsheave M to a point where another load of loose material may begathered. When the scoop E has reached a predetermined point of itsmovement toward the tail sheave M, the operator R then manipulates theactuator bar 80 to move the switch arm 71 to its off position and theswitch arm 76 to one of its on positions in connection with eitherswitch contact 77 or 78, whereby to release the high torque transfercoupling 16 and set the coupling 17. It should be borne in mind that theend of the cable 0 is slidable on the rod P of the scoop'E so that thecable 0 may be used to pull the scoop in a forward or backward directionwith equal facility and without tending to turn the: scoop E end forend. The cable 0 pulls the scoop E forwardly along the gallery G untilthe scoop reaches the intersection between the gallery G and corridor H,the cable D meanwhile being wound upon the drum A under rotation of thedrum A imparted thereto by the low torque transfer coupling 38associated therewith. When thescoop E reaches said intersection, theoperator then manipulates the actuator bar 80 to move the switch arm 76to its 05 position and the switch, arm 71 into connection with thecontact 72 to set the high torque transfer coupling 15 of the drum A tomove the scoop forwardly through the corridor H to the hopper I, thuscompleting a single cycle of operation. It should be noted that theroller N prevents the return cable K from rubbing against the rough wallduring the forward movement of the scoop E through the corridor H, andlikewise prevents the pull-forward cable D from rubbing against thecorner during the movement of the scoop E through the gallery G towardthe tail sheave M.

It should further be noted that the switching arrangement is such thatthe high torque transfer couplings l5 and 16 cannot be setsimultaneously. This is a pre The high torque transfer cautionarymeasure designed to prevent breaking of the cables K or B if the samewere to be placed under pulling load of their respective high torquetransfer couplings at the same time. The high torque transfer couplingsof the drums A and C may be set for simultaneous operation as may thetransfer couplings of the drums B and C for controlling and guiding thescoop E along selected paths. The operator is, in these instances, underthe necessity of being alert to prevent pulling of any of these cablesin opposition to another cable which is under pulling tension of theirrespective high torque couplings. The pressure relief or regulator valve27 may be assumed to be set to allow all of the high torque transfercouplings to carry a predetermined maximum load. This maximum load willnecessarily be less than that necessary to cause damage to any of theparts in the event that the operator fails to control the machineproperly. The actuator bar 80 enables the operator to have perfectcontrol over the high torque transfer couplings with one hand andmovement of the bar 80 to any of its dotted line positions of Fig. 12will cause the machine to function as desired. As shown in Figs. 11, 12and 14, movement of the actuator bar 80 to its full line position ofthese figures releases all of the several high torque transfer couplingsand effectively stops all movement of the scoop E. The function of theseveral low torque transfer couplings in causing otherwise slack cablesto be wound on the drums associated therewith, permits sudden reversalof the direction of travel of the scoop E at any point in its travelsmoothly and without jerking, thus the scoop can be made to travel atrelatively high speeds so as to convey a maximum amount of material witha minimum time consumptron.

In the arrangement illustrated in Figs. 15 and 16, the scoop S is shownas being connected to adjacent ends of a pair of cables D and [A'.] K.In this arrangement, I utilize a pair of drums C and C", identical inall respects to the drum C and having driving connections and mountingmeans identical to that of the drum C. This arrangement is particularlyadapted for moving granular material in the holds of ships, long storagebins of certain elevators, and the like. For controlling the drums C andC", I provide respective solenoid operated valves 96 and 97 which areinterposed in a fluid pressure line similar to that described inconnection with Figs. 2 and 3. The valves 96 and 97 admit air underpressure to high torque transfer couplings 98 and 99 associated withtheir respective drums C and C". The low torque transfer couplingsassociated with the drums C and C" are not shown in detail but areindicated in Fig. 15 at 100 and 101, respectively.

A control circuit for the valves 96 and 97 comprises a pair of leads 102and 103, a pair of switches 104 and 105, a master control switch 106 andbranch leads 107, 108 and 109. As shown, the leads 102 and 103 areadapted to -be connected one each to the opposite sides of a twowirepower line 110. The lead 102 is common to both switches 104 and lwherebyclosing of the switch 104 will cause the valve 97 to set the high torquetransfer coupling 99 by being energized through the lead 102, switch104, the lead 107, the solenoid associated with the valve 97 and thelead 103. On the other hand, the valve 96 is operated to set the hightorque transfer coupling 98 associated with the drum C by closing of theswitch 105, whereby to cause the circuit to be closed through the lead102, the switch 105, lead 108, the sole noid associated with the valve96, lead 109 and a portion of lead 103.

The switches 104 and 105 are of the push button type mounted in a commoncontrol box 11 which may be carried by the operator in the manner of thecontroller 83 and which is provided with a push button 112 associatedwith the switch 104 and a like push button 113 which is associated withthe switch 105. The push buttons 112 and 113 are connected to theopposite ends of a lever 8 114, which asdiagrammatically shown, ispivotally se' cured at its center in the control box 111, as indicatedat 115. With this arrangement, closing of either of the switches 104 andwill positively open the other thereof, thereby precluding anypossibility of both of the high torque transfer couplings 98 and 99being set at the same time. The several leads of the control circuit arecontained within suitable cables 116 and 117 leading from the machinesto the control box 111 so that the operator is free to position himselfto the best advantage. in the operation of this arrangement of myconveyor machines. Obviously, other arrangements such as that shown inmy co-pending application above identified will suggest themselves to aperson skilled in the art.

In the modified arrangement shown in Fig. 17, the low torque transfercoupling 41 is altered by the removal of the plates 52 and 59 from theirrespective arms 53 and 58. As shown, a rigid link 118 is connected atone end to the depending lug 61 by means of a nut-equipped bolt 119 andat its other end is anchored to the supporting frame 3 by a nut-equippedbolt 120. Otherwise, the parts illustrated in Fig. 17 are identical tocorresponding parts of Figs. 1 to 10, inclusive, and bear like referencecharacters. With this arrangement, a frictional load of relatively lowtorque is placed upon the winding drum in both directions of itsrotation. This arrangement prevents backlash during unwinding of thecable from the drum, but is not intended to pick up slack which mightoccur in the cable. For this reason, the bar 118 may very convenientlybe substituted for the plates 52 and 59 when the machine is used asillustrated in Fig. 15.

While I have shown and described a preferred arrangement and severalmodifications of my improved shovelling or conveying machine, it will beunderstood that the same is capable of further modification within thespirit and scope of the invention as defined in the claims.

What I claim is:

1. In a device of the class described, a supporting structure; a windingdrum journaled for rotation on the supporting structure; a drive shaft;power transmission mechanism connecting the drive shaft to the windingdrum, said power transmission mechanism including a low torque transferfriction coupling comprising relatively rotary driving and drivenelements, the former of which isconnected to the drive shaft and thelatter of which is connected to the drum, and a releasable high torquetransfer coupling connecting the drive shaft to the drum; and means forvarying the torque transferability of said low torque transfer coupling,said means comprising an adjustment member operative to increase ordecrease the frictional load applied by one of said elements to theother thereof.

2. In a device of the class described, a supporting structure; a windingdrum journaled for rotation on the supporting structure, a drive shaft,power transmission mechanism connecting said drive shaft to said windingdrum, said power transmission mechanism including a low torque frictiontransfer coupling comprising relatively rotary driving and drivenelements, the former of which 'is connected to the drive shaft and thelatter of which is connected to the drum and a releasable high torquetransfer coupling connecting the drive shaft to the drum, the torquetransferability of the releasable high torque transfer coupling beingsufiicient to overcome the resistance of a work load of predeterminedvalue, and the low torque transfer coupling delivering a maximum torqueinsufficient to drive said load while producing a sufficient dragbetween the shaft and drum to drive the drum in the absence of said loadand to prevent overrunning -of the drum when paying out cable in adirection of rdtation opposite that of the shaft, and means for varyingthe torque transferability of said low torque transfer coupling belowthe maximum deliver thereof, said means comprising an adjustment memberon one of said elements operative to increase or decrease the frictionalload applied by one of said elements to the other thereof.

3. In a device of the class described, a supporting structure, a windingdrum journaled for rotation on the supporting structure, a continuouslyoperating constant speed drive shaft, and power transmission mechanismconnecting said drive shaft to said winding drum, said powertransmission mechanism including a low torque friction transfer couplingcomprising relatively rotary driving and driven elements, the former ofwhich is connected to the drive shaft and the latter of which isconnected to the drum, and a releasable high torque transfer couplingconnecting the drive shaft to the drum, and means for varying the torquetransferability of said low torque transfer coupling, said meanscomprising an adjustment member on one of said elements and operative toincrease or decrease the frictional load applied thereby to the other ofsaid elements.

4. In a device of the class described, a supporting structute, a driveshaft journaled in said supporting structure, a winding drum journaledon said drive shaft, power transmission mechanism connecting said driveshaft to said winding drum, said power transmission mechanism includinga. low torque friction transfer coupling comprising relatively rotarydriving and driven elements, the former of which is connected to thedrive shaft and the latter of which is connected to the drum, areleasable high torque transfer coupling connecting the drive shaft tothe drum, and means for varying the torque transferability of said lowtorque transfer coupling, said means comprising an adjustment member onone of said elements operative to increase or decrease the frictionalload applied thereby to the other of said elements.

5. In a device of the class described, a supporting structure, a windingdrum journaled for rotation on the supporting structure, a drive shaft,power transmission mechanism connecting the drive shaft to the windingdrum, said power transmission mechanism including a low torque transferfriction coupling comprising relatively rotary driving and drivenelements, the former of which is connected to the drive shaft and thelatter of which is connected to the drum, one of said elements having aworking face and the other of said elements including a friction shoemovable toward and away from operative engagement with said workingface, adjustable means urging said shoe toward engagement with saidworking face, and a releasable high torque transfer coupling connectingthe drive shaft to the drum.

6. In a device of the class described, a supporting structure, a driveshaft journaled in said supporting structure, a winding drum journaledon said drive shaft, power transmission mechanism connecting said driveshaft to said winding drum, said power transmission mechanism includinga low torque friction transfer coupling comprising relatively rotarydriving and driven elements, the former of which is connected to thedrive shaft and the latter of which is connected to the drum, saiddriven element having a cylindrical working face, said driving elementincluding a circumferentially extended friction shoe radiallycontractable and expansible toward and away from operative engagementwith said working face, adjustable means urging said shoe towardoperative engagement with said working face, and a releasable hightorque transfer coupling connecting the drive shaft to the drumindependently of said low torque transfer coupling.

7. In a device of the class described, a supporting structure, a driveshaft journaled in said supporting structure, a winding drum journaledon said drive shaft, power transmission mechanism connecting said driveshaft to said winding drum, said power transmission mechanism includinga hub on said winding drum having a cylindrical working face, aband-like friction shoe enengaging said working face, means couplingsaid friction shoe to said drive shaft for common rotation therewith,yielding means biasing said friction shoe toward frictional engagementwith said working face, means for varying the bias of said yieldingmeans, said shoeaud working face providing a low torque transfercoupling, and a releasable high torque transfer coupling connecting thedrive shaft to the drum independently of said low torque transfercoupling.

8. A system for conveying bulk material, comprising a pair of cablewinding drums each journaled for independent rotatiton, a bulk loadmoving member, a cable operatively connected to said member and with thefree ends thereof connected to each of said drums for winding thereonand moving said member in opposite directions between said drums, rotarydriving means, coupling means connecting each of said drums with thedriving means including releasable high torque means and low torquemeans, and an independent actuator operably connected to each of saidhigh torque means for setting and releasing the same with respect to thedriving means, each of said low torque means being eflective to maintaintension on its respective drum and cable portion when the cooperatinghigh torque means is inefiective and the high torque means of the otherdrum is efiectively connecting the respective drum to the driving means.

9. A system for conveying bulk material, comprising a pair of cablewinding drums each journaled for independent rotation, a bulk loadmoving member, a cable operably connected with said member and with thefree ends of said cable connected to each of said drums for windingthereon and moving said member in opposite directions, rotary drivingmeans, coupling means connecting each of said drums with the drivingmeans including a releasable high torque means and a low torque means,an independent actuator operably connected to each of said high torquemeans for setting and releasing the same with respect to the drivingmeans, and control means operatively connected to each of said actuatorsand adapted to alternately render one of said actuators eflective to setits respective high torque means and simultaneously render the otheractuator inefiective to release its respective high torque means, eachof said low torque means being eflective to maintain tension on itsrespective drum and cable portion when the cooperating high torque meansis ineffective and the high torque means of the other drum iseflectively connecting the respective drum to the driving means.

10. A system for conveying bulk material, comprising a pair of cablewinding drums each journaled for independent rotation, a bulk loadmoving member, a cable operably connected to said member and with thefree ends thereof connected to each of said winding drums for windingthereon and moving said member relative to said drums, rotary drivingmeans, coupling means connecting each of said drums with the drivingmeans including releasable high torque means and low torque means, anindependent actuator operably connected to each of the high torque meansfor setting and releasing the same relative to the rotary driving means,and control means operably connected to both of said actuators andadapted V to alternately render one of said actuators effective to setits respective high torque means and simultaneously render the otheractuator inefiective to release its respective high torque means, eachof said low torque means being eflective to maintain tension on itsrespective drum and cable portion when the cooperating high torque meansis inefl'ective and the high torque means of the other drum iseffectively connecting the respective drum to the driving means.

11. A system for conveying bulk material, comprising a pair of cablewinding drums each journaled for independent rotation, a bulk loadmoving member, a cable operably connected to said member and with thefree ends thereof connected to each of said winding drums for windingthereon and moving said member relative to said drums, rotary drivingmeans, coupling means connecting each of said drums with the drivingmeans including releasable high torque means and low torque means, anindependent actuator operably connected to each of the high torque meansfor setting and releasing the same relative to the rotary driving means,and control means for operating said actuators to set and release thehigh torque means comprising a circuit including said actuators,independent switches in said circuit operably connected to each of saidactuators, and mechanical means connecting both of said switches andwhen one of the switches is closed is effective to maintain the otherswitch simultaneously open and assure that only onehigh torque couplingmeans is efiective at any one time, each of said low torque means beingeflective to maintain tension on its respective drum and cable portionwhen the cooperating high torque means is ineffective and the hightorque means of the other drum is effectively connecting the respectivedrum to the driving means.

12. A system for conveying bulk material, comprising three cable windingdrums each journaled for independent rotation, a bulk load movingmember, cable means connected to said bulk moving member and to each ofthe respective drums for winding thereon and moving said member in adirection relative to said drums, a rotary driving means for each ofsaid drums, coupling means connecting each of said drums with thedriving means including releasable high torque means and low torquemeans, and an independent actuator operably connected to each of saidhigh torque means for setting and releasing the same with respect to thedriving means, each of said low torque means being effective to maintaintension on its respective drum and cable portion when the cooperatinghigh torque means is ineffective and the high torque means of one of theother drums is eflectively connecting the respective drum to the drivingmeans.

13. A system for conveying bulk material, comprising three cable windingdrums each journaled for independent rotation, a bulk load movingmember, cable means connected to said bulk moving member and to each ofthe respective drums for winding thereon and moving said member in adirection relative to said drums, a rotary driving means for each ofsaid drums, coupling means connecting each of said drums with thedriving means including releasable high torque means and low torquemeans, an independent actuator operably connected to each of the hightorque means for setting and releasing the same relative to the rotarydriving means, and control means operably connected to each of saidactuators and adapted to alternately render one of said actuatorsefiective to set its respective high torque means and simultaneouslyrender the other two actuators ineflective to assure release of theirrespective high torque means and assure that only one of said actuatorscan be efiective at any one time, each of said low torque means beingeffective to maintain tension on its respective drum and cable portionwhen the cooperating high torque means is ineffective and the hightorque means of one of the other drums is efiectively connecting therespective drum to the driving means.

14. A system for conveying bulk material, comprising three cable windingdrums each journaled for independent rotation, a bulk load movingmember, cable means connected to said bulk moving member and to each ofthe respective drums for winding thereon and moving said member in adirection relative to said drums, a rotary driving means for each ofsaid drums, coupling means connecting each of said drums with thedriving means including releasable high torque means and low torquemeans, an independent actuator operably connected to each of the hightorque means for setting and releasing the same relative to the rotarydriving means, and control means for operating said actuators,comprising a circuit including said actuators, an independent switch insaid circuit for each of the actuators, and mechanical means operablyconnected to all of said switches and adapted to render two of saidswitches inefiective when the other switch is set to energize itsrespective actuator, and to assure release of the remaining high torquemeans when the said one high torque means is set, each of said lowtorque means being eflective to maintain tension on its respective drumand cable portion when the cooperating high torque means is inefiectiveand the high torque means of one of the other drums is efiectivelyconnecting the respective drum to the driving means.

15. A cable winding machine, comprising a cable winding drum journaledfor rotatable movement, a rotatable driving member, and coupling meansconsisting of a releasable high torque means adapted to connect thedriving member with the drum when the latter is engaged in a cablewinding operation, and a predetermined adjustable low torque meanscontinuously connecting said driving member and said drum to maintain apredetermined force on said drum when the high torque means is released.

16. A cable winding machine, comprising a cable winding drum journaledfor rotatable movement, a rotatable driving member, and coupling meansconsisting of a releasable high torque means adapted to connect thedriving member and the drum when the latter is engaged in a cablewinding operation, and a predetermined adjustable constant force lowtorque means continuously connecting said driving member and the drum tomaintain a constant preadjusted low torque on said drum when the hightorque means is released.

17. A cable winding machine, comprising a cable winding drum journaledfor rotatable movement, a rotatable driving shaft, coupling meansconsisting of a releasable high torque clutch adapted to connect thedriving shaft and the drum when the latter is engaged in a cable windingoperation, a low torque clutch continuously connecting said drivingshaft and said drum, and means operatively connected with said lowtorque clutch for adjusting the torque thereof to maintain a low torqueon said drum when the high torque clutch is released.

18. A cable winding machine, comprising a driving -shaft journaled forrotatable movement, a cable winding drum circumscribing said shaftbetween its opposite ends, coupling means including a releasable hightorque clutch disposed on one side of said drum and adapted toselectively connect said shaft and drum when the latter is engaged in acable winding operation, a low torque clutch disposed on the other sideof said drum from the high torque clutch and continuously connectingsaid shaft and said drum for rotating said drum in a direction oppositeto the direction of rotation when the high torque clutch is operative,and means operatively connected to said low torque clutch for adjustingthe torque thereof to maintain a low torque on said drum when the hightorque clutch is released.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 2,349,914 Peale et a1. May 30, 1944 2,418,006Bangert, Jr Mar. 25, 1947 2,536,483 Young Jan. 2, 1951 2,542,533Johansson Feb. 20, 1951 2,602,635 Young July 8, 1952 2,635,851 MaierApr. 21, 1953

